This invention relates to valves used to control the flow of process media, and more particularly, to a Lubrication system for a gate valve wherein movement of the gate valve causes the movement of lubricant through a lubricant passageway which is then provided to valve sealing members to lubricate the valve sealing members.
Gate valves or knife gate valves are used to control the flow of fluid, such as slurries and other process media, in a pipeline. Such valves include a housing having a fluid passageway and a moveable gate for opening or closing the fluid passageway. The gate is configured to slide between a pair of opposed sealing sleeves that are located within the housing. In an open position, the gate is moved out from between the sealing sleeves thus opening the fluid passageway and enabling the flow of fluid between inlet and outlet ports of the valve. When this occurs, ends of the sealing sleeves move axially and contact each other to form a seal to inhibit leakage of fluid. In a closed position, the gate is moved in between the sealing sleeves to thus close the fluid passageway. In this position, the sealing sleeves seal the gate to inhibit leakage of fluid.
The gate valve may also include a secondary seal to seal the gate valve. The secondary seal acts to inhibit fluid, which may seep through the sealing sleeves, from leaking around the gate or toward an actuator end of the gate valve. It is desirable to lubricate the sealing sleeves in order to optimize performance and extend their life. A technique used to lubricate the sealing sleeves involves applying a lubricant to the secondary seal. Contact between the gate and the secondary seal then transfers lubricant to the gate. The gate then transfers lubricant to the sealing sleeves via contact between the gate and the sealing sleeves. It is desirable to provide improved techniques for lubricating the secondary seal.